Sentences with phrase «ice sheet albedo forcing»

Ice sheet albedo forcing is estimated to have caused a global mean forcing of about — 3.2 W m — 2 (based on a range of several LGM simulations) and radiative forcing from increased atmospheric aerosols (primarily dust and vegetation) is estimated to have been about — 1 W m — 2 each.

So how much of the temperature swings are orbitally forced and how much GHG forced and how much ice sheet albedo forced?

Not exact matches

On the studies of sensitivity based on the last glacial maximum, what reduction in solar forcing is used based on the increased Albedo of the ice - sheets, snow and desert.

26 Paul W asked, «On the studies of sensitivity based on the last glacial maximum, what reduction in solar forcing is used based on the increased Albedo of the ice - sheets, snow and desert.

This implies a forcing of 3 W / m2 for albedo changes presumably due to additional ice / snow sheets.

This was a relatively stable climate (for several thousand years, 20,000 years ago), and a period where we have reasonable estimates of the radiative forcing (albedo changes from ice sheets and vegetation changes, greenhouse gas concentrations (derived from ice cores) and an increase in the atmospheric dust load) and temperature changes.

On the studies of sensitivity based on the last glacial maximum, what reduction in solar forcing is used based on the increased Albedo of the ice - sheets, snow and desert.

In LGM simulations land albedo changes are prescribed (at least in regards to ice sheets and altered topography due to sea level; there are feedback land albedo changes) so are a forcing, whereas sea ice is determined interactively by the model climate, so is a feedback in this framework.

As I explained, you * can * get at climate sensitivity with the ice core record, but only by taking into account all the forcing (including, in particular, the ice sheet albedo).

(Orbital forcing doesn't have much of a global annual average forcing, and it's even concievable that the sensitivity to orbital forcing as measured in terms of global averages and the long - term response (temporal scale of ice sheet response) might be approaching infinity or even be negative (if more sunlight is directed onto an ice sheet, the global average albedo might increase, but the ice sheet would be more likely to decay, with a global average albedo feedback that causes warming).

Orbital forcing causes ice ages or ends them by redistributing incoming solar radiation over seasons and latitudes so that ice sheet growth or decay is more or less favorable on a regional basis, with a resulting global average albedo feedback.)

So albedo change (owing to changes in orbital forcing, which is what melts the ice sheets) was comparable to, and probably larger than, the CO2 change.

article, Hansen estimates that the radiative forcing from all greenhouse gases together (glacial - interglacial) is -2.6 + / - 0.5 W / m ^ 2, and ice sheet albedo is -3.5 + / -1 W / m ^ 2.

From the last glacial max — CO2 forcing had about a 2W / m2 increase and ice sheet albedo change amounted to some 25W / m2 less reflected SW..

Comparisons of the impacts of shortwave and longwave radiative forcing appropriate over the ice sheets are not straightforward, but taking summer half - year insolation variations in shortwave (Figure 3), and assuming an albedo of 0.5 for melting ice, variations in summertime shortwave forcing exceed the direct CO2 radiative forcing by about a factor of five.

Albedo change due to LGM — Holocene vegetation change, much of which is inherent with ice sheet area change, and albedo change due to coastline movement are lumped together with ice sheet area change in calculating the surface albedo climate foAlbedo change due to LGM — Holocene vegetation change, much of which is inherent with ice sheet area change, and albedo change due to coastline movement are lumped together with ice sheet area change in calculating the surface albedo climate foalbedo change due to coastline movement are lumped together with ice sheet area change in calculating the surface albedo climate foalbedo climate forcing.

Another way of saying this is to estimate ECS from the last glacial - interglacial transition, the albedo change due to ice sheet melting is taken as a forcing rather than as a feedback.